Tower furnace reciprocating feed

ABSTRACT

Apparatus for reciprocating the feed mechanism for a tower furnace in order to obtain a dropping pattern of feed material which will produce a ceramic foam slab with a substantially flat upper surface.

United States Patent m1 Siemssen et al.

1 TOWER FURNACE RECIPROCATING FEED [75] inventors: Ernst A.Siemssen,Gwne1Z1;'J6hn M. Hummel,Doylestown, both of [73] Assignee: Selas Corporation of America,

Dresher, Pa.

22 Filed: Aug. 17,1971

21 Appl. No.: 172,489

[52] US. Cl. 432/14, 214/18 V, 214/35 R. 432/239, 432/58 [51] Int. Cl. F27b 3/18 [58] Field of Search 263/21 B, 29; 214/18 V, 35 R, 17 C [56] References Cited UNITED STATES PATENTS 9/1955 Kuilet a1. 214/17C Aug. 28, 1973 Gerber .l 214/17 c 2,178,418 10/1939 Brown et a1 214/35 R Primary Examiner-John J. Camby Assistant Examiner-Henry C. Yuen Attorney-E. Wellford Mason [57] ABSTRACT Apparatus for reciprocating the feed mechanism for a tower furnace in order to obtain a dropping pattern of feed material which will produce a ceramic foam slab with a substantially flat upper surface.

6 Claims, 2 Drawing Figures Patented Aug. 28, 1973 3,754,855

1 TOWER FURNACE RECIPROCATING FEED BACKGROUND AND SUMMARY The present invention relates to the operation of tower furnaces, and more particularly to a method and apparatus for dropping particles to be bloated through a furnace in a pattern to produce a ceramic foam product having a substantially flat top surface.

When operating a tower furnace it is customary to drop small particles of a clay composition, or other material that will bloat upon heating, through orifices in the top of the furnace. The particles are heated to bloating temperature, and bloat, as they fall. When making a ceramic foam slab, the particles, still tacky on their surfaces, are collected on a moving belt. During their fall through the furnace the particles tend to spread slightly, but mounds are still formed vertically below the orifices. This results in the top surface of the slab of foam having a series of humps and ridges transversely across its surface. The finished slab must then be cut to give it a flat surface, with the resulting cost and loss of material.

It is an object of this invention to provide a method and means for dropping particles through a tower furnace in such a manner that the resulting slab product has a substantially flat top surface.

It is a further object of the invention to provide a means to reciprocate a plurality of feed orifices transverselyof a tower furnace. It is also an object of the invention to provide means to shift the supplies of particles in a tower furnace back and forth across the furnace.

In practicing the invention a tower furnace is provided with a feed slot extending across the top of the furnace. Located above the slot is a plate having a plurality of feed orifices therein, aligned with said slot. Means is provided to reciprocate the plate slowly in the direction of the feed slot, thereby moving the orifices 'to shift the locations from which the particles are dropped.

The various features of novelty which characterize our invention are pointed out with particularity in the claims annexed to and forming a part of this specifica: tion. For a better understanding of the invention, however, its advantages, and specific objects attained with its use, reference should be had to the'accompanying drawings and descriptive matter in which we have illustrated and described a preferred embodiment of the invention.

IN THE DRAWINGS FIG. 1 is a section taken on line 11 of FIG. 2. FIG. 2 is a section taken on line 2-2 of FIG. 1.

DETAILED DESCRIPTION Referring to the drawings, the number 1 indicates a tower furnace, only the upper and lower portions of which have been shown. The furnace is normally from to 30 feet high and consists of a vertically extending furnace chamber, opposite sides of which are provided The belt is preferably made of metallic mesh to with.- stand the temperatures that are encountered and it is shown as being driven from one end by a roll 6, with the edges of the belt beyond the sides of the furnace being supported for horizontal travel on a pair of rails 5. Asv shown herein, the belt with the product on it is moved to the right in FIG. 2 from beneath the furnace into an annealing section7 in which the product is annealed. There is also provided to the left of the furnace a hopper 8 in which a parting agent 9, such as sand, is deposited in a layer on the belt prior to the time it moves into the lower portion of the furnace chamber.

The upper end of the chamber is provided with a feed slot 11 which extends transversely in the direction of belt movement. This slot is covered by a cover plate 12 that consists of a structural steel frame 13 filled with a refractory material 14. The cover plate is mounted for reciprocation in the direction of the slot. To this end, the ends of the frame 13 are provided with plates 15 that rest upon suitably mounted rollers 16.

The cover plate 12 is provided with a plurality of feed orifices 17 that are supplied with the material to be heated through flexible tubes 18, the upper ends of which are connected to a supply hopper. It is noted that the lower ends of the feed tubes are held in position over the feed orifices by means of brackets 21. The cover plate with its feed orifices is reciprocated in the direction of the slot and transversely to the belt .by means of a constant speed, reversible motor 22 that is mounted on a suitable frame 23. This motor drives .a threaded shaft 24 that is journaled in and held from axial movement by bearings 25 fastened to frame 23. As the shaft is rotated a sleeve 26 is moved axially thereof. This sleeve is attached to an arm 27 fastened to one of the plates 15. Thus, as the shaft is rotated the sleeve 26 will be reciprocated and the cover plate will be reciprocated therewith. Sleeve 26 has an actuating pin 28 projecting upwardly therefrom. As the sleeve is moved back and forth this actuating pin will strike one or another of limit switches 29 and 30 which serve to reverse the direction of travel of the motor and the movement of the cover plate and its feed orifices. The limit switches can be adjusted along frame 23 in order to determine the stroke of the cover.

In the operation of the furnace, small clay particles, or similar material that will bloat or be fused, will be loaded in hopper 19. The particles flow through tubes 18 and orifices 17 to fall through the furnace. As the particles fall through the furnace chamber they are heated to fusion temperature and bloat into small spherical bodies. These bodies collect on belt 4 to a thickness depending upon the volume of the supply of particles and the speed of the belt. The particles stick together to form a cellular product known as ceramic foam. The belt moves the product through annealing oven 7 where it is cooled before being cut tosize.

' In previous furnaces of this type, the particles were supplied to the furnace through stationary orifices located in various patterns in the top of the furnace. With each of the prior patterns of orifices the collected particles produced a slab with an upper surface having a plurality of ridges and depressionsiacross the strip. This non-uniform thickness of the slab can cause a variation in the texture of the productas well as result in considerable waste in the product when it is cut to a uniform thickness.

With the use of the present invention the feed orifices 17 are moved at a uniform speed back and forth transversely of the furnace. Thus, the pattern of the falling particles is such that they form a slab 32 having a substantially flat top surface with a relatively sharp cut-off at the edges. In one embodiment of the invention, orifices 17 are spaced 6 inches apart and the orifices are reciprocated through a distance of 6 inches at a speed of 1 inch a second. Regardless of the spacing of the feed orifices, the distance that they are moved as they are reciprocated is a multiple of the spacing of the orifices.

Motor 22 runs at a constant speed and is periodically reversed as pin 28 operates either one or the other of limit switches 29 and 30. As mentioned above, these switches can be adjusted along frame 23 to vary the stroke of cover-12 and the feed orifices.

While in accordance with the provisions of the Statutes we have illustrated and described the best form of embodiment of our invention now known to us, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit and scope of the invention set forth in the appended claims, and that in some cases certain features of our invention may be used to advantage without a corresponding use of other features.

What is claimed is:

1. In combination, a tower furnace having an upper end and a lower end, means forming aligned openings in opposite sides of said lower end, a collecting belt extending through said openings across the lower end of said furnace, means to move said belt, said belt having a substantially flat horizontal collecting surface, the

upper end of said furnace being provided with a feed slot extending transversely of said belt, a cover plate over said slot, means to reciprocate said cover plate in the direction of said slot, said cover plate being provided with a plurality of feed orifices aligned with said slot whereby as said cover plate is reciprocated said orifices are moved back and forth along said slot, and means to supply particles to be heated to said orifices.

2. The combination of claim 1 in which said means to reciprocate said cover plate is operated at a constant speed in each direction.

3. The combination of claim 1 including means to limit the operation of said means to reciprocate in each direction, said means to limit being adjustable thereby to vary the distance through which said cover plate is moved.

4. The method of operating a tower furnace which comprises dropping feed material to be heated vertically downwardly in free fall in a plurality of individual streams, locating said streams in a row transversely of the furnace, and continuously reciprocating said streams in the direction of said row as the feed material is falling.

5. The method of claim 4 in which said streams are separated a predetermined distance apart, and in which the distance said streams are moved as they are reciprocated is a multiple of said predetermined distance.

6. The method of claim 4 including collecting the dropped material in a slab having a substantially flat upper surface at the lower end of the furnace and removing it from the furnace in a direction transverse to the direction of the reciprocation of the feed streams. 

1. In combination, a tower furnace having an upper end and a lower end, means forming aligned openings in opposite sides of said lower end, a collecting belt extending through said openings across the lower end of said furnace, means to move said belt, said belt having a substantially flat horizontal collecting surface, the upper end of said furnace being provided with a feed slot extending transversely of said belt, a cover plate over said slot, means to reciprocate said cover plate in the direction of said slot, said cover plate being provided with a plurality of feed orifices aligned with said slot whereby as said cover plate is reciprocated said orifices are moved back and forth along said slot, and means to supply particles to be heated to said orifices.
 2. The combination of claim 1 in which said means to reciprocate said cover plate is operated at a constant speed in each direction.
 3. The combination of claim 1 including means to limit the operation of said means to reciprocate in each direction, said means to limit being adjustable thereby to vary the distance through which said cover plate is moved.
 4. The method of operating a tower furnace which comprises dropping feed material to be heated vertically downwardly in free fall in a plurality of individual streams, locating said streams in a row transversely of the furnace, and continuously reciprocating said streams in the direction of said row as the feed material is falling.
 5. The method of claim 4 in which said streams are separated a predetermined distance apart, and in which the distance said streams are moved as they are reciprocated is a multiple of said predetermined distance.
 6. The method of claim 4 including collecting the dropped material in a slab having a substantially flat upper surface at the lower end of the furnace and removing it from the furnace in a direction transverse to the direction of the reciprocation of the feed streams. 